Evaluation of Bioequivalency and Pharmacokinetic Parameters for Two Formulations of Glimepiride 1-mg in Chinese Subjects.

PURPOSE: Glimepiride, an FDA-approved oral hypoglycemic drug, is a long-acting sulfonylurea (SU), used for treating type 2 diabetes. The study aimed to evaluate the bioequivalence and safety profiles of two different formulations of glimepiride 1 mg from two different manufactures in healthy Chinese subjects in the fasting and fed state in order to acquire adequate pharmacokinetic evidence for registration approval of the test formulation. PATIENTS AND METHODS: This study is an open-label, two-period, two-sequence, randomized, two-way crossover pharmacokinetic study in healthy Chinese subjects in the fasting and fed state. Seventy-two subjects were randomly assigned to the fasting group and the fed group (n=36 each). We collected blood samples, 24-h post drug administration. The plasma concentration of glimepiride was assessed using HPLC coupled with mass spectrometry. The following parameters were evaluated: AUC0-inf, AUC0-last, Cmax, t1/2, Tmax, and λz. Safety was determined based on the occurrence of adverse events (AEs) and laboratory examinations (biochemistry, hematology, and urinalysis) throughout the entire study period. RESULTS: The geometric mean ratios (GMR) amongst the two glimepiride formulations for the primary pharmacokinetic parameters, ie, AUC0-inf, AUC0-last, and Cmax as well as the corresponding 90% CIs, were all within the range of 80.00-125.00% in the fasting and fed state. The safety profile for both treatments was comparable. CONCLUSION: PK analysis revealed that the test and reference formulations of glimepiride were bioequivalent and well tolerated in healthy Chinese subjects. Chinese Clinical Trials Registry identifier: CTR20171121. CLINICAL TRIAL REGISTRATION NUMBER: CTR20171121.

Determination of grapiprant plasma and urine concentrations in horses.

OBJECTIVE: Non-steroidal anti-inflammatory drugs are inhibitors of cyclooxygenase (COX) in tissues and used as therapeutic agents in different species. Grapiprant, a member of the piprant class of compounds, antagonizes prostaglandin receptors. It is a highly selective EP4 prostaglandin E2 receptor inhibitor, thereby limiting the potential for adverse effects caused by wider COX inhibition. The objectives of this study were to determine if the approved canine dose would result in measurable concentrations in horses, and to validate a chromatographic method of analysis for grapiprant in urine and plasma. STUDY DESIGN: Experimental study. ANIMALS: A total of six healthy, adult mixed-breed mares weighing 502 ± 66 (397-600) kg and aged 14.8 ± 5.3 (6-21) years. METHODS: Mares were administered one dose of 2 mg kg-1 grapiprant via nasogastric tube. Blood and urine samples were collected prior to and up to 48 hours after drug administration. Drug concentrations were measured using high-performance liquid chromatography. RESULTS: Grapiprant plasma concentrations ranged from 71 to 149 ng mL-1 with the mean peak concentration (106 ng mL-1) occurring at 30 minutes. Concentrations were below the lower limit of quantification (50 ng mL-1) in four of six horses at 1 hour and in all six horses by 2 hours after drug administration. Grapiprant urine concentrations ranged from 40 to 4077 ng mL-1 and were still detectable at 48 hours after administration. CONCLUSIONS AND CLINICAL RELEVANCE: Currently, there are no published studies looking at the pharmacodynamics of grapiprant in horses. The effective concentration needed to control pain in dogs ranges 114-164 ng mL-1. Oral administration of grapiprant (2 mg kg-1) in horses did not achieve those concentrations. The dose was well tolerated; therefore, studies with larger doses could be conducted.

Magnetic solid phase extraction followed with LC-MS/MS for determination of glimepiride in beagle dog plasma and its application to bioequivalence study.

In this study, the core-shell polydopamine-coated magnetic nanomaterials were synthesized with one-step approach and applied as magnetic solid phase extraction adsorbents combined with LCMS/MS for quantification of the diabetes drug glimepiride in beagle dog plasma. The Fe3O4@PDA nanomaterials have strong magnetic response, good dispersibility in aqueous solution, and numerous binding sites for π-π interaction and hydrogen bonding with glimepiride. Based on these merits, glimepiride could be quickly extracted and separated from plasma within 10min. The established method has good linearity (1-2000ng•mL-1), low quantification limit (1ng•mL-1), good precision (RSDs≤12 %), and satisfactory extraction recovery (71.20-85.70 %). Moreover, we successfully applied this method to the bioequivalence study of generic and innovator products of glimepiride in beagle dog plasma.

Simultaneous determination of metformin and glimepiride in human serum by ultra high performance liquid chromatography quadrupole time of flight mass spectrometry detection.

This work proposes a simple method for the simultaneous determination of two antidiabetic compounds, metformin and glimepiride, by ultra-high performance liquid chromatography using quadrupole time of flight mass spectrometry detection with electrospray ionization. The method was validated and shown to be linear, selective, accurate and precise. The chromatographic separation was performed using a BEH C18 column (50 mm x 2.1 mm, 1.7 µm particle size). The mobile phase was composed by 0.05% (v/v) aqueous formic acid solution and acetonitrile using a gradient elution program, at a flow rate of 0.3 mL/min. Linearity range for metformin was 1.7-100 µg·L-1, using propranolol as internal standard and 3.3-100 µg·L-1 for glimepiride using glibenclamide as internal standard. Limits of detection and lower limits of quantitation were 0.4 µg·L-1 and 1.7 µg·L-1 for metformin and 0.7 and 3.3 µg·L-1 for glimepiride, respectively. The method was used for the simultaneous determination of these compounds in human serum samples with lower limits of detection and quantitation than serum levels reported in previous works that allows its applicability in therapy drug monitoring.

Pharmacokinetics of grapiprant, a selective EP4 prostaglandin PGE2 receptor antagonist, after 2 mg/kg oral and i.v. administrations in cats.

Drugs that provide effective analgesia in cats are limited. The aim of the study was to assess the pharmacokinetics of grapiprant after 2 mg/kg administration via p.o. and i.v. routes in cats. Six healthy adult cats were used according to an open, single-dose, two-treatment, two-period, randomized cross-over design. Cats were assigned to two treatment groups and administered with 2 mg/kg of grapiprant (pure powder) through p.o. and i.v. administration. Blood samples were collected at preassigned times and analysed by a validated HPLC method. After both administrations, grapiprant concentrations were detectable in plasma for up to 24 hr in five of six animals. The critical parameters including clearance (173.2 ml hr-1  kg-1 , range 120-326 ml hr-1  kg-1 ) and volume of distribution (918 ml/kg, range 611-1608 ml/kg) were calculated from the i.v. group. The mean oral F% was low (39.6% range 31.5%-45.2%). If the assumption that the minimal effective concentration in dogs (164 ng/ml) applies in cats too, grapiprant orally administered at 2 mg/kg might be effective for 10 hr. Further studies are necessary to establish the minimal effective concentration in this animal species.

A validated LC-MS/MS method for the estimation of glimepiride and pitavastatin in rat plasma: Application to drug interaction studies.

Glimepiride (GLI) is prescribed for the management of type-2 diabetes where as pitavastatin (PIT) for the treatment of diabetes associated dyslipidemia. Both the drugs are metabolized by CYP2C9 and have the potential of altering the enzyme through either inhibition or induction. In this respect, we present a simple, fast and validated bioanalytical LC-MS/MS method for the simultaneous estimation of GLI and PIT from rat plasma. Waters XTerra RP HPLC column (4.6×100mm, 5µm) with mobile phase consisting of acetonitrile and 10mM ammonium acetate (pH-6.0) in the ratio 85:15 (v/v) at a flow rate of 1mL/min was used for the chromatographic separation. The negative ionization mode with MRM transitions: m/z 420.17→288.13 for PIT, m/z 489.59→350.12 for GLI and m/z 380.08→316.31for celecoxib as internal standard (IS). A total run time of 3min and LLOQ was found to be 5ng/mL for both PIT and GLI. The method was applied to study the drug interaction between GLI and PIT in rat liver microsomes. In vivo rat pharmacokinetics study showed there was a 1.29-fold increase in AUC0-∞ and 1.2-fold decrease in the clearance of PIT in presence of GLI. No notable difference in the pharmacokinetic profile of GLI was observed upon the intravenous co-administration of PIT.

Development of Solid-Phase Extraction and HPLC Method for Simultaneous Estimation of Ilaprazole and Glimepiride in Rat Plasma: Application to Pharmacokinetic Studies.

A novel, simple and mass spectrometry (MS) compatible high-performance liquid chromatography (HPLC) method is reported for the simultaneous estimation of ilaprazole (ILA) and glimepiride (GLM) in rat plasma. The bio-analytical procedure involves extraction of ILA, GLM and internal standard (IS) from rat plasma with a solid-phase extraction (SPE) process. The chromatographic analysis was performed on Waters-600 system using an isocratic mobile phase comprising methanol:water (80:20 % v/v) with pH of water modified to three using formic acid at a flow rate of 1.0 mL/min and Kinetex C18 column maintained at 30 ± 1°C. The signals were monitored using a PDA detector set at 225 nm. IS, ILA and GLM eluted at 2.04, 4.7 and 7.4 min, respectively, and the total run time was 10 min. Method validation was performed as per US Food and Drug Administration guidelines and the results met the acceptance criteria. The calibration curve was linear over a concentration range of 10-600 ng/mL (r2 = 0.999). The intra- and inter-day precisions for ILA and GLM were (%RSD values) in the range of 1.52-9.74 and 1.52-11.76%, respectively, in rat plasma. The method was successfully applied in pharmacokinetic studies followed by oral administration of GLM and ILA in rats.

Simultaneous Determination of Bosentan, Glimepiride, HYBOS and M1 in Rat Plasma by UPLC-MS-MS and its Application to Pharmacokinetic Study.

A rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method for the simultaneous determination of bosentan (BOS), glimepiride (GLP), hydroxyl bosentan (HYBOS) and hydroxyl glimepiride (M1) in rat plasma using one-step protein precipitation was developed and validated. After addition of ambrisentan as an internal standard (IS), protein precipitation by acetonitrile was used in sample preparation. Chromatographic separation was achieved on a Waters ACQUITY UPLC BEH C18 column (2.1 mm × 100 mm, 1.7 µm particle size, Waters Corp., Milford, MA, USA) and inline 0.2 µm stainless steel frit filter (Waters Corp.) with acetonitrile-0.1% formic acid as the mobile phase at a flow rate of 0.4 mL/min with gradient elution. The column temperature was maintained at 40°C. Only 4 min was needed for an analytical run. The retention times were ∼3.29 min for BOS, 3.56 min for GLP, 1.42 min for HYBOS, 1.53 min for M1 and 3.22 min for IS. Electrospray ionization source was employed and operated in positive-ion mode; multiple reaction monitoring mode was applied to target fragment ions m/z 552 → 202, m/z 568 → 202, m/z 491 → 352, m/z 507 → 352 and m/z 379 → 347 for BOS, HYBOS, GLP, M1 and IS, respectively. The assay was validated over concentration ranges of 25-5,000 ng/mL (r(2) = 0.9984) for BOS, 1-200 ng/mL (r(2) = 0.9999) for GLP, 0.5-100 ng/mL (r(2) = 0.9999) for HYBOS and 0.1-20 ng/mL (r(2) = 0.9984) for M1. Intra- and interday precision values for replicate quality control samples were within 14.2% for all analytes during the assay validation. Mean quality control accuracy values were within -3.3 to 14.4% of nominal values for all analytes. The mean recoveries of BOS, GLP, HYBOS, M1 and ambrisentan from the plasma exceeded 90.4%. The analytes were stable in rat plasma for at least 2 h at room temperature, 30 days at -40°C and following at least three freeze-thaw cycles (-40°C to room temperature). This method was successfully applied to a pharmacokinetic study of coadministeration of BOS and GLP in rats.

Pharmacokinetic comparison of oral tablet and suspension formulations of grapiprant, a novel therapeutic for the pain and inflammation of osteoarthritis in dogs.

A new anti-inflammatory drug for pain (grapiprant) was recently shown to have minimal side effects following chronic (9-month) daily oral dose of 6 or 50 mg/kg suspension. The current study compares the pharmacokinetics of the formulation used in the chronic safety study to those of the tablet formulation that will be marketed upon FDA approval. Sixteen Beagle dogs were randomized to receive single doses of either 6 or 50 mg/kg grapiprant as both suspension and table formulations within a cross-over design with a 15-day washout. Clinical observations were vomiting in one high-dose suspension dog and loose stools in two dogs, one in each 6 mg/kg formulation group. For both formulations, grapiprant reached a maximum concentration within two hours. The tablet formulation had better bioavailability, with AUClast values 34% higher at 6 mg/kg and 64% higher at 50 mg/kg compared to the suspension. Results on Day 0 were similar to those reported on Day 15, suggesting little to no accumulation. Using conversion factors of 1.34 and 1.64, these findings suggest that the 6 and 50 mg/kg suspension doses are equivalent to 4.5 and 30 mg/kg tableted doses, respectively. Combining these findings with the 9-month safety study demonstrates that safety was evaluated at doses approximately 15-fold above the demonstrated therapeutic dose of 2 mg/kg and 10-fold over the 'safety dose', defined as the maximum dose a dog of any body weight could receive when dosed at 2 mg/kg with whole or half-tablets.

Transdermal glimepiride delivery system based on optimized ethosomal nano-vesicles: Preparation, characterization, in vitro, ex vivo and clinical evaluation.

This work aimed to develop an optimized ethosomal formulation of glimepiride then loading into transdermal films to offer lower drug side effect, extended release behavior and avoid first pass effect. Four formulation factors were optimized for their effects on vesicle size (Y1), entrapment efficiency (Y2) and vesicle flexibility (Y3). Optimum desirability was identified and, an optimized formulation was prepared, characterized and loaded into transdermal films. Ex-vivo permeation study for the prepared films was conducted and, the permeation parameters and drug permeation mechanism were identified. Penetration through rat skin was studied using confocal laser microscope. In-vivo study was performed following transdermal application on human volunteers. The percent of alcohol was significantly affecting all the studied responses while the other factors and their interaction effects were varied on their effects on each response. The optimized ethosomal formulation showed observed values for Y1, Y2 and Y3 of 61 nm, 97.12% and 54.03, respectively. Ex-vivo permeation of films loaded with optimized ethosomal formulation was superior to that of the corresponding pure drug transdermal films and this finding was also confirmed after confocal laser microscope study. Permeation of glimepiride from the prepared films was in favor of Higushi-diffusion model and exhibited non-Fickian or anomalous release mechanism. In-vivo study revealed extended drug release behavior and lower maximum drug plasma level from transdermal films loaded with drug ethosomal formulation. So, the ethosomal formulation could be considered a suitable drug delivery system especially when loaded into transdermal vehicle with possible reduction in side effects and controlling the drug release.

Development and validation of an LC-MS/MS sulfonylurea assay for hypoglycemia cases in the emergency department.

BACKGROUND: Sulfonylureas are antidiabetic agents widely prescribed for the treatment of type-II diabetes. Detection of the presence of sulfonylureas in cases of unexplained hypoglycemia rules out other underlying pathophysiological conditions. The goal of this study was to develop and validate a qualitative liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for the rapid identification of sulfonylureas in serum. METHODS: An LC-MS/MS assay was developed using an Agilent HPLC with an AB Sciex 3200 LC-MS/MS operating in ESI positive mode. Linearity, LOD, precision, matrix effect, recovery, carry-over and stability of the final method were evaluated for method validation. Concordance with another clinically validated LC-MS/MS method was evaluated using remnant samples from patients prescribed a sulfonylurea. RESULTS: The assay performed well with all validation data meeting pre-determined criteria. The method comparison study showed a correlation coefficient of 0.99 for glipizide, the most common sulfonylurea, despite both methods being validated as qualitative methods. To date the validated assay has been utilized in 19 cases of unexplained hypoglycemia presenting to the emergency department, in which 5 were sulfonylurea positive. CONCLUSION: We have developed a rapid and sensitive LC-MS/MS sulfonylurea assay, and utilized this assay to assist in the differential diagnosis of unexplained hypoglycemia.

Effect of ranolazine on glycaemic control in patients with type 2 diabetes treated with either glimepiride or metformin.

AIM: To report the results of two phase III trials assessing the efficacy of ranolazine for glycaemic control in patients with type 2 diabetes on metformin or glimepiride background therapy. METHODS: In two double-blind trials we randomized 431 and 442 patients with type 2 diabetes to ranolazine 1000 mg twice daily versus placebo added to either glimepiride (glimepiride add-on study) or metformin background therapy (metformin add-on study). Patients receiving ranolazine added to metformin had their metformin dose halved (with the addition of a metformin-matched placebo) relative to the placebo group to correct for a metformin-ranolazine pharmacokinetic interaction. The primary endpoint of the trials was the change from baseline in glycated haemoglobin (HbA1c) at week 24. RESULTS: When added to glimepiride, ranolazine caused a 0.51% least squares mean [95% confidence interval (CI) 0.71, 0.32] decrease from baseline in HbA1c at 24 weeks relative to placebo and roughly doubled the proportion of patients achieving an HbA1c of <7% (27.1 vs 14.1%; p = 0.001). When added to metformin background therapy, there was no significant difference in the 24-week HbA1c change from baseline [placebo-corrected LS mean difference -0.11% (95% CI -0.31, 0.1)]. CONCLUSIONS: Compared with placebo, addition of ranolazine in patients with type 2 diabetes treated with glimepiride, but not metformin, significantly reduced HbA1c over 24 weeks. The decreased dose of metformin used in the metformin add-on study complicates the interpretation of this trial. Whether an effective regimen of ranolazine added to metformin for glycaemic control can be identified remains unclear.

Effects of Gymnema sylvestre extract on the pharmacokinetics and pharmacodynamics of glimepiride in streptozotocin induced diabetic rats.

Gymnema sylvestre, important Indian traditional herbal medicine has been used for diabetes from several years and marketed as single or multi-herb formulations globally. People are consuming G. sylvestre along with conventional hypoglycemic drugs. Therefore, there is need of evidence based assessment of risk versus benefits when G. sylvestre co-administered with conventional oral hypoglycemic drugs. In present investigation, pharmacodynamics and pharmacokinetic interactions with oral hypoglycemic drug, glimepiride (GLM) was studied in streptozotocin (STZ) induced diabetic rats. A specific and rapid HPLC-ESI-MS/MS method was established for simultaneous quantification of GLM and gymnemagenin (GMG) in rat plasma. Pharmacokinetic and pharmacodynamic interaction studies were carried out in STZ induced diabetic rats after concomitant administration of 400 mg/kg of G. sylvestre extract and 0.8 mg/kg of GLM for 28 days. The developed HPLC-ESI-MS/MS method was rapid, specific, and precise. Con-comitant oral administration of G. sylvestre extract (400 mg/kg) and GLM (0.8 mg/kg) in diabetic rats for 28 days showed beneficial pharmacodynamic interactions whereas no major alterations in the pharmacokinetics parameters of GLM and GMG were observed. This interaction demonstrated in animal model implies that significant clinical outcome might occur during concomitant administration of G. sylvestre extract and GLM especially in diabetic patients and warrants further studies in the same set up.

Effect of Piperazine Dithioctate on the Oral Pharmacokinetics of Glimepiride in Rats.

The objective of the present work was to investigate the potential for pharmacokinetic drug-drug interactions between glimepiride (GMP) and piperazine dithioctate (PDT) in rats to support the development of an orally combined product of the two drugs. An LC-MS/MS bioanalytical method was developed for simultaneous quantification of GMP and thioctic acid (TA) in rat plasma. The accuracy, precision, linearity, selectivity, and recovery were all within an acceptable range. The oral plasma exposure of the GMP solution was more than 14-times greater than that of the GMP suspension at a dose of 0.5 mg/kg, suggesting a dissolution-limited absorption of the GMP suspension. Oral co-administration of PDT (72 mg/kg) with GMP suspension (0.5 mg/kg) reduced the plasma GMP exposure by approximately 80% without a significant change in t1/2 and tmax. Oral co-administration of PDT with GMP solution had no significant effect on the plasma pharmacokinetics of GMP. PDT lowered the pH (from ca. 7 to 5.6) and the dissolved GMP concentration in the GMP suspension. It was also shown that GMP was more soluble at pH 7 than at 5.7 in an aqueous solution, and the oral plasma exposure of a GMP suspension at pH 7.0 was substantially higher than that of a suspension at pH 5.7. These results suggest that the pH-dependent solubility of GMP was likely responsible for PDT's effect on the oral absorption of GMP. In conclusion, the current work suggests a possibility of drug-drug interaction between GMP and PDT upon oral co-administration.

An UPLC-MS/MS method for the analysis of glimepiride and fluoxetine in human plasma.

A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to determine glimepiride (GPD) and fluoxetine (FLU) in human plasma using diazepam as the internal standard (IS) simultaneously. The presented method used an Acquity UPLC BEH C18 column for chromatographic separation with tandem mass spectrometric detection on a QTrap5500 mass spectrometer operated in positive ESI mode. The mobile phase is a mixture of acetonitrile and 1% formic acid in water with gradient elution at a flow rate of 0.40mL/min. The GPD, FLU and IS were eluted at 1.46, 1.27 and 1.39min, respectively. The MRM transitions of m/z 491.3→126.3 and m/z 310.5→148.1 were used to quantify for GPD and FLU, respectively. The linearity of this method was found to be within the concentration range of 2.5-300ng/mL and 0.1-20ng/mL for GPD and FLU in human plasma, respectively. The intra- and inter-day precision (RSD%) were less than 10.3% and accuracy (RE%) was within ±7.3%. The matrix effect were 95.3-100.7% for GPD and FLU. GPD and FLU were sufficiently stable under all relevant analytical conditions. The method was also successfully applied to the clinical samples after a single oral dose of 2mg GLP and 40mg FLU in patients.

Simultaneous determination of oral antidiabetic drugs in human plasma using microextraction by packed sorbent and high-performance liquid chromatography.

In this study, a simple method using microextraction by packed sorbent and high-performance liquid chromatography with ultraviolet detection for simultaneous determination of chlorpropamide, gliclazide and glimepiride in human plasma was developed and validated. A fractional factorial design and a complete factorial design were applied to evaluate the parameters which could affect the extraction and desorption steps, respectively. All parameters in the extraction step (pH, sample volume, sample dilution and number of aspiration/ejection cycles) and in the desorption step (percentage of acetonitrile in the elution solvent and number of aspirations of elution solvent through the device) were statistically significant (p>0.05) when recovery was used as response. The developed method allowed the use of small volumes of sample and solvents and rapid separation by using a fused core column (only 2.2min were needed). This method was fully validated showing selectivity, precision, accuracy and linearity over the range 1.0-50.0µgmL(-1) for chlorpropamide, 1.0-10.0µgmL(-1) for gliclazide and 0.1-1.0µgmL(-1) for glimepiride. Finally, the validated method was applied in the analysis of samples from volunteers containing the three tested analytes.

Simultaneous determination of glimepiride and pioglitazone in human plasma by liquid chromatography-tandem mass spectrometry and its application to pharmacokinetic study.

The rapid, sensitive, and selective liquid chromatography-electrospray ionization-tandem mass spectrometry method (LC-ESI-MS/MS) for the simultaneous estimation and pharmacokinetic investigation of glimepiride and pioglitazone in human plasma has been developed and fully validated. Glimepiride and pioglitazone, compounds which exert synergistic effects on blood glucose control, were investigated in human plasma using deuterium-labeled analogs as internal standards (IS). Liquid-liquid extraction was carried out on 0.2 mL of human plasma using ethyl acetate, and chromatographic separation was performed on an Agilent Eclipse plus C18 column (4.6 mm × 100 mm, 3.5 µm) using a mobile phase consisting of methanol-water-formic acid (95:5:0.1, v/v/v, plus 5mM ammonium acetate) at a flow rate of 0.8 mL/min. To quantify glimepiride, pioglitazone and their IS, multiple reaction monitoring (MRM) transitions of m/z 491.2→352.2, m/z 496.2→357.2, m/z 357.2→134.2 and m/z 361.2→138.2 were performed in positive mode. The total run time was 3.0 min and the elution time was about 2.4 min. The method exhibited good separation of analytes, without interference from endogenous substances. The linear calibration curves were 0.2-250 ng/mL for glimepiride and 0.2-1,250 ng/mL for pioglitazone; the lower limit of quantification (LLOQ) was 0.2 ng/mL for both analytes. Intra- and inter-day reproducibility was less than 10% for glimepiride and less than 5% for pioglitazone, with relative errors ranging from -8.00% to 2.80% at the three concentrations of analytes used for quality control (QC). The matrix effect was negligible and recoveries were similar for each analyte and its IS. Glimepiride and pioglitazone were found to be stable under the assay conditions and the method was successfully applied to the evaluation of pharmacokinetic studies of glimepiride and pioglitazone, following oral doses of 2mg glimepiride tablets and 15 mg pioglitazone tablets to 16 healthy volunteers.

Simultaneous determination of bosentan and glimepiride in human plasma by ultra performance liquid chromatography tandem mass spectrometry and its application to a pharmacokinetic study.

A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to determine bosentan (BOS) and glimepiride (GPD) in human plasma simultaneously. Chromatographic separation was carried out on an Acquity UPLC BEH C18 column and mass spectrometric analysis was performed using a QTrap5500 mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transitions of m/z 552.0→202.1 and m/z 491.2→125.9 were used to quantify BOS and GPD, respectively. This assay method has been fully validated in terms of selectivity, linearity, recovery and matrix effect, accuracy, precision and stability. The linearity of this method was found to be within the concentration range of 5-1000 ng/mL for BOS, and 2.5-500 ng/mL for GPD in human plasma. Only 1.5 min was needed for an analytical run. This assay was used to support a clinical study where multiple oral doses were administered to healthy Chinese subjects to investigate the pharmacokinetics of BOS and GPD.

[A case of hypoglycemia caused by the accidental ingestion of glimepiride in an elderly dementia patient diagnosed based on the serum glimepiride concentration].

A 77-year-old man being treated for Alzheimer-type dementia and an old cerebral infarction was admitted to our hospital due to disturbance of consciousness. The patient's Mini-mental State Examination and Hasegawa Dementia Scale scores were 23 and 17 points, respectively. His blood glucose level was low (18 mg/dl), with a relatively high insulin level (15.2 µU/ml). Computed tomography and an 18-hour fasting test showed no signs of insulinoma. Since his wife had been taking medications for dementia and diabetes, including Glimepiride, we considered the possibility that he may have taken glimepiride by mistake. Five months later, he was admitted again due to severe hypoglycemia with a relatively high insulin level (23.4 µU/ml). More than 660 g of glucose and 100 mg of hydrocortisone were administered, and the hypoglycemia resolved approximately 24 hours after admission. Again, there were no signs of insulinoma. We asked Sanofi-Aventis to measure the level of glimepiride in a blood sample obtained six hours after admission. Glimepiride was detected at a concentration of 24.48 ng/ml, which roughly corresponded to the accidental ingestion of 6 mg of the drug. We were later informed by the patient's home doctor that he had visited the emergency department of another prefecture hospital with the same symptoms. Thereafter, the couple received counseling by their home doctor, and the hypoglycemia has not recurred since. Given the increase in the number of elderly households, an increase in the number of episodes of accidental ingestion of medicine is expected. Clinicians should be aware of the potential for accidental exposure to drugs prescribed to other family members especially, in elderly patients.